The purpose of this project is to determine if adenosine A1 and GABA-B receptors, both of which are negatively coupled to adenylate cyclase, interact when they are associated with the same neuronal cells. Our present objective is to determine if the nonadditive responses to stimulation of adenosine A1 and GABA-B receptors in striatum and cerebellum are the result of both receptors being found on the same cell type and perhaps coupled to the same cyclase catalytic unit.